[lxc-devel] [PATCH] introduce lxcapi_rename for renaming containers

[Serge Hallyn]

Quoting Stéphane Graber (stgraber at ubuntu.com):
> On Mon, Dec 16, 2013 at 02:37:11PM -0500, S.Çağlar Onur wrote:
> > Hi Serge,
> > 
> > On Mon, Dec 16, 2013 at 9:47 AM, Serge Hallyn <serge.hallyn at ubuntu.com> wrote:
> > > Quoting S.Çağlar Onur (caglar at 10ur.org):
> > >> lxcapi_rename implemented as a convenience function as lately
> > >> I find myself in a need to rename a container due to a
> > >> typo in its name. I could have started over but didn't want
> > >> to spend more time (to installing extra packages and changing
> > >> their configuration) on it.
> > >>
> > >> c->clone() followed by c->destroy() did the trick for me and I
> > >> though it could be helpful to the other people, so here it is.
> > >>
> > >> Signed-off-by: S.Çağlar Onur <caglar at 10ur.org>
> > >
> > > Looks ok, but should you be specifying LXC_CLONE_COPYHOOKS |
> > > LXC_CLONE_KEEPMACADDR  as clone flags?
> > 
> > I thought I should to be keeping the container intact as much as I
> > can, assuming something might be using those values (like
> > redhat/centos/fedora ifcfg-* files where you could specify HWADDR)
> 
> I'm not sure about LXC_CLONE_COPYHOOKS but LXC_CLONE_KEEPMACADDR should
> actually go towards your goal of having the copy be as close to the
> original as possible (without it, the mac address would be changed).

Yeah.  Çağlar, lemme know if you agree.

> > 
> > >> ---
> > >>  src/lxc/lxccontainer.c | 33 +++++++++++++++++++++++++++++++++
> > >>  src/lxc/lxccontainer.h | 10 ++++++++++
> > >>  2 files changed, 43 insertions(+)
> > >>
> > >> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> > >> index 6326724..1af8d62 100644
> > >> --- a/src/lxc/lxccontainer.c
> > >> +++ b/src/lxc/lxccontainer.c
> > >> @@ -2596,6 +2596,38 @@ out:
> > >>       return NULL;
> > >>  }
> > >>
> > >> +static bool lxcapi_rename(struct lxc_container *c, const char *newname)
> > >> +{
> > >> +     struct bdev *bdev;
> > >> +     struct lxc_container *newc;
> > >> +     int flags = LXC_CLONE_KEEPMACADDR | LXC_CLONE_COPYHOOKS;
> > >> +
> > >> +     if (!c || !c->name || !c->config_path)
> > >> +             return false;
> > >> +
> > >> +     bdev = bdev_init(c->lxc_conf->rootfs.path, c->lxc_conf->rootfs.mount, NULL);
> > >> +     if (!bdev) {
> > >> +             ERROR("Failed to find original backing store type");
> > >> +             return false;
> > >> +     }
> > >> +
> > >> +     newc = lxcapi_clone(c, newname, c->config_path, flags, NULL, bdev->type, 0, NULL);
> > >> +     bdev_put(bdev);
> > >> +     if (!newc) {
> > >> +             lxc_container_put(newc);
> > >> +             return false;
> > >> +     }
> > >> +
> > >> +     if (newc && lxcapi_is_defined(newc))
> > >> +             lxc_container_put(newc);
> > >> +
> > >> +     if (!lxcapi_destroy(c)) {
> > >> +             ERROR("Could not destroy existing container %s", c->name);
> > >> +             return false;
> > >> +     }
> > >> +     return true;
> > >> +}
> > >> +
> > >>  static int lxcapi_attach(struct lxc_container *c, lxc_attach_exec_t exec_function, void *exec_payload, lxc_attach_options_t *options, pid_t *attached_process)
> > >>  {
> > >>       if (!c)
> > >> @@ -3139,6 +3171,7 @@ struct lxc_container *lxc_container_new(const char *name, const char *configpath
> > >>       c->wait = lxcapi_wait;
> > >>       c->set_config_item = lxcapi_set_config_item;
> > >>       c->destroy = lxcapi_destroy;
> > >> +     c->rename = lxcapi_rename;
> > >>       c->save_config = lxcapi_save_config;
> > >>       c->get_keys = lxcapi_get_keys;
> > >>       c->create = lxcapi_create;
> > >> diff --git a/src/lxc/lxccontainer.h b/src/lxc/lxccontainer.h
> > >> index 3e1b492..b7c5313 100644
> > >> --- a/src/lxc/lxccontainer.h
> > >> +++ b/src/lxc/lxccontainer.h
> > >> @@ -326,6 +326,16 @@ struct lxc_container {
> > >>                       struct bdev_specs *specs, int flags, ...);
> > >>
> > >>       /*!
> > >> +      * \brief Rename a container
> > >> +      *
> > >> +      * \param c Container.
> > >> +      * \param newname New name to be used for the container.
> > >> +      *
> > >> +      * \return \c true on success, else \c false.
> > >> +      */
> > >> +     bool (*rename)(struct lxc_container *c, const char *newname);
> > >> +
> > >> +     /*!
> > >>        * \brief Request the container reboot by sending it \c SIGINT.
> > >>        *
> > >>        * \param c Container.
> > >> --
> > >> 1.8.3.2
> > >>
> > >> _______________________________________________
> > >> lxc-devel mailing list
> > >> lxc-devel at lists.linuxcontainers.org
> > >> http://lists.linuxcontainers.org/listinfo/lxc-devel
> > > _______________________________________________
> > > lxc-devel mailing list
> > > lxc-devel at lists.linuxcontainers.org
> > > http://lists.linuxcontainers.org/listinfo/lxc-devel
> > 
> > 
> > 
> > -- 
> > S.Çağlar Onur <caglar at 10ur.org>
> > _______________________________________________
> > lxc-devel mailing list
> > lxc-devel at lists.linuxcontainers.org
> > http://lists.linuxcontainers.org/listinfo/lxc-devel
> 
> -- 
> Stéphane Graber
> Ubuntu developer
> http://www.ubuntu.com



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